help

by kathy
(lake st louis)

Each of the 50 campers could earn 1 of 3 different types of boating badges. Of all the campers, 20% got sailing badges, 50% earned rowing badges, and 10% received canoeing badges. How many campers did not earn a badge for some sort of boating?

Here's My Answerby Zach(Singapore)

Step 1: This question involves the Part-Whole Concept and the Percentage Concept. For percentage questions, it is usually easily to comprehend by converting the percentages into fractional parts.

Since 20% got sailing badges, we draw 2 boxes to represent 20% of the campers, 50% got rowing badges, we draw 5 boxes to represent 50% of the campers, 10% got canoeing badges, we draw 1 box to represent 10% of the campers.

Thus, the remaining 20% should have not gotten any badges, so we draw 2 boxes to represent 20% of the campers. We then draw a bracket to the right of the model to show the total of 50 campers.